Structural flooring panel and floor structure incorporating the same

ABSTRACT

A structural flooring panel comprises an upper sheet, a lower sheet and a plurality of longitudinally extending ribs between the sheets. The ribs are laterally spaced to define at least one longitudinally extending, internal channel within the panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/180,713 to Taraba et al. filed on May 22, 2009, the content of whichis incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to building structures and inparticular, to a structural flooring panel and to a floor structureincorporating the same.

BACKGROUND OF THE INVENTION

In residential homes and other building structures, floors are typicallyconstructed by fastening one or more sheets of a wood-based material,such as plywood or oriented strand board (“OSB”), to laterally spaced,longitudinally extending lumber joists. The joists are oriented toprovide increased strength and resist bending, as is known in the art.

Ducting for heating, ventilation, and air-conditioning is typicallyincorporated into the building structure once the floors have beenconstructed. This involves affixing one or more primary ventilationducts to the underside of the joists, and running secondary ductsstemming from the primary ducts between joists.

Recently, structural building panels have become an increasingly commonmaterial for use in the construction of residential homes and otherbuilding structures due to their low cost, high strength, high energyefficiency, and ease of installation. Structural insulated panels(“SIPs”) are one form of structural building panel, and have asandwich-type structure comprising two sheets typically of a wood-basedmaterial, such as plywood or OSB, adhesively bonded to opposite sides ofan inner slab of foam insulation. Expanded polystyrene (“EPS”) istypically used for the foam insulation, with extruded polystyrene andpolyurethane foam sometimes being used. When used during theconstruction of walls, the bonded sandwich structure of SIPs has beendemonstrated to provide comparable strength to conventional wallscomprising a lumber stud frame filled with fiberglass insulation. SIPsare typically fabricated as sheets of a standard size (e.g. 4 feet×8feet), which can then be cut to size on-site as needed prior toinstallation.

Structural building panels for use as flooring panels have also beenconsidered. For example, U.S. Pat. No. 6,279,287 to Meadows discloses aprefabricated building panel including first and second side panelmembers. A thermally insulating core is disposed between the side panelmembers. A first panel end surface includes a pair of spaced projectionsdefining a channel-way. A second panel end surface includes a pair ofspaced channels and a thermal barrier plug. Two adjacent building panelsmay be interconnected by engaging the pair of spaced projections at thefirst end of the first panel with the pair of spaced channels in thesecond end of the second panel while simultaneously engaging thethermally insulating plug at the second end of the second panel in thechannel-way at the first end of the first panel.

U.S. Pat. No. 6,564,521 to Brown et al. discloses a structural sandwichpanel wherein during fabrication, facing sheets are placed in positionin a containment form assembly and a foam resin core material isinjected between the facing sheets and allowed to cure. The resultantstructural sandwich panel includes elongated recesses which form a jointfor joining abutting structural sandwich panels together and cam-locksto secure adjoining structural sandwich panels together.

U.S. Pat. No. 6,599,621 to Porter discloses a generally flat structuralpanel for building construction including an inner insulating core suchas plastic foam and a pair of opposed outer facings, or sheets, bondedto the insulating core. One of the outer facings is of gypsum composite,or gypsum fiberboard, while the other outer facing is of oriented strandboard (OSB) impregnated with plastic, such as a polyisocyanurate orurethane resin. The gypsum fiberboard forms the panel's inner surface,while the plastic impregnated OSB forms the panel's outer surface. Thepanel's outer facings provide high tensile strength, with the gypsumfiberboard facing also affording high load bearing capacity as well asresistant to fire, the environment, and insects. The plastic impregnatedOSB does not expand or contract with changes in humidity to maintain aplanar configuration for the structural panel with a smooth, uniformsurface for exterior finishing.

U.S. Patent Application Publication No. 2007/0125042 to Hughes et al.discloses a structural insulated laminated construction panel forbuilding structures comprising a rigid core material layer, preferablyan expanded polystyrene material, having opposed flat parallel surfaces.

As will be appreciated, the structural building panels described in theabove references have a closed structure. As a result when a floorstructure is constructed using these structural building panels, ductingfor heating, ventilation, and air conditioning cannot be readilyintegrated into the floor structure. Consequently, all ducting must beaffixed to the external surfaces of the flooring structure. This adds tothe total quantity of material used in the construction of the buildingstructure, and increases its overall cost. Additionally, ducts that areaffixed to the external surfaces of the flooring structure can be bulky,and can reduce the overhead clearance in rooms. As will be appreciated,improvements in structural flooring panels are desired.

It is therefore an object of the present invention to provide a novelstructural flooring panel and a novel floor structure incorporating thesame.

SUMMARY OF THE INVENTION

Accordingly, in one aspect there is provided a structural flooring panelcomprising an upper sheet; a lower sheet; and a plurality oflongitudinally extending ribs between the sheets, the ribs beinglaterally spaced to define at least one longitudinally extending,internal channel within the panel.

In one embodiment, the ribs define a plurality of longitudinallyextending, internal channels within the panel, with the internalchannels being generally parallel. The internal channels also extendgenerally the length of the panel.

In one embodiment, at least one passage is provided through at least oneof the ribs to bring adjacent internal channels into fluidcommunication. In another embodiment, at least one passage is providedthrough at least one of the upper and lower sheets, with the at leastone passage being in fluid communication with an internal channel.

In one form, each of the ribs comprises a pair of rib sheets andinsulation between the rib sheets. Each of the rib sheets is bonded toan opposite side of the insulation. The rib sheets of each rib areoriented so that the planes of their major surfaces are generallyperpendicular to the planes of the major surfaces of the upper and lowersheets. In another form, each rib comprises a slab of insulation and arib sheet bonded to one side of the slab of insulation.

According to another aspect, a floor structure is provided thatcomprises a plurality of abutting structural flooring panels asdescribed above. The abutting structural flooring panels are arrangedside-by-side and end-to-end. In one arrangement, the internal channelsof the end-to-end structural flooring panels are axially aligned and inan alternative arrangement the internal channels of the end-to-endstructural flooring panels are axially offset. The abutting structuralflooring panels may also carry mating formations.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described more fully with reference to theaccompanying drawings in which:

FIG. 1 a is a cross-sectional side view of a building structureincorporating structural flooring panels;

FIG. 1 b is an enlarged portion of FIG. 1 a.

FIGS. 2 a and 2 b are side elevational and top plan views of a floorstructure formed of a plurality of abutting structural flooring panels;

FIGS. 3 a, 3 b, and 3 c are front elevational, top plan and sideelevational views, respectively, of one of the structural flooringpanels forming the floor structure of FIGS. 2 a and 2 b;

FIG. 4 is a cross-sectional perspective view of a portion of thestructural flooring panel of FIGS. 3 a to 3 c;

FIG. 5 is a front elevational view of the structural flooring panel ofFIGS. 3 a to 3 c;

FIGS. 6 a and 6 b are front elevational views of a joint between twoadjacent structural flooring panels forming part of the floor structureof FIGS. 2 a and 2 b;

FIGS. 7 a and 7 b are front elevational views of site-crafted jointsbetween two adjacent structural flooring panels forming part of a floorstructure;

FIG. 8 is a front elevational view of a portion of another embodiment ofa structural flooring panel;

FIGS. 9 a, 9 b, and 9 c are front elevational, top plan and sideelevational views, respectively, of yet another embodiment of astructural flooring panel;

FIGS. 10 a, 10 b, and 10 c are front elevational, top plan and sideelevational views, respectively, of yet another embodiment of astructural flooring panel;

FIGS. 11 a, 11 b, and 11 c are front elevational, top plan and sideelevational views, respectively, of yet another embodiment of astructural flooring panel; and

FIGS. 12 a, 12 b, and 12 c are front elevational, top plan and sideelevational views, respectively, of still yet another embodiment of astructural flooring panel.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following discussion relates a structural flooring panel for use ina building structure comprising two sheets separated by a plurality oflaterally spaced, generally parallel ribs. The ribs are spaced so as toprovide structural support for the structural flooring panel and todefine longitudinally extending, internal channels within the structuralflooring panel. A floor structure can be easily and quickly assembledusing the structural flooring panels. Heated or cooled air can be forcedthrough the internal channels within the structural flooring panels toprovide a heated or cooled floor structure.

Turning now to FIGS. 1 a to 2 b, a building structure is shown and isgenerally identified by reference numeral 10. In this embodiment, thebuilding structure 10 is a house and comprises a foundation slab 12surrounded by foundation walls 14 that are supported on footings 16below the foundation slab 12. First and second floor structures 18 and20 are provided within the building structure 10 at different elevationsand are surrounded by external walls 22. Structural flooring panels 24are used to construct the floor structures 18 and 20. In particular,each floor structure comprises an array of structural flooring panels 24arranged side-to-side and end-to end as best seen in FIG. 2 a. Thelength of each structural flooring panel 24 is selected so that the endsof the structural flooring panel 24 are either supported by the exteriorwalls 22 or by support beams 26 as shown in FIG. 2 a.

Turning now to FIGS. 3 a to 5 one of the structural flooring panels 24is better illustrated. As can be seen, structural flooring panel 24comprises an upper sheet 32 and a lower sheet 34 separated by aplurality of laterally and generally equally spaced, longitudinallyextending, generally parallel ribs 36 adhesively bonded to the sheets.In the embodiment shown, sheets 32 and 34 are formed of oriented strandboard (“OSB”) or other suitable material such as for example plywood,medium density fiberboard, particle-board, concrete sheet,magnesium-based sheet etc. The spacing of the ribs 36 is selected so asto provide the structural flooring panel 24 with sufficient structuralsupport and resist bending against vertically-imposed loads to complywith the strength requirements of local building codes while at the sametime to define a plurality of longitudinally extending, internalchannels 38 within the structural flooring panel 24.

Each rib 36 has a “sandwich” structure comprising two rib sheets 40,each of which is adhesively bonded to an opposite side of a slab ofinsulation 42. In this embodiment, the rib sheets 40 are formed of awood-based material, such as OSB, plywood, fiberboard, particle-boardetc. The insulation slab 42 is formed of suitable material, such asexpanded polystyrene, honeycomb cardboard, extruded polystyrene,polyurethane foam, and the like. The planes of the major surfaces of therib sheets 40 are perpendicular to the planes of the major surfaces ofthe upper and lower sheets 32, 34. This orientation of each rib 36relative to the sheets 32 and 34 takes advantage of the high in-planestrength of the rib sheets 40, which stiffens the structural flooringpanel 24 and contributes to its high bending strength.

Opposite sides of the upper and lower sheets 32 and 34 carry formationsso that when the structural flooring panel 24 is brought side-to-sidewith another similar structural flooring panel, the formations on theupper and lower sheets of the abutting structural flooring panels mate.In particular, a longitudinally extending tongue 44 is provided on oneside of the upper sheet 32 and a longitudinally extending groove 46 isprovided in the opposite side of the upper sheet 32. The side of thelower sheet 34 beneath the tongue 44 is notched to define a lower lapmember 48 while the side of the lower sheet 34 beneath the groove 46 isnotched to define an upper lap member 50.

FIGS. 6 a and 6 b show the joint between two adjacent structuralflooring panels 24 when arranged in a side-by-side manner. As can beseen, when the two structural flooring panels 24 are positioned withtheir longitudinal sides in an abutting relationship, the abutting sidesof the upper sheets 32 form a tongue-and-groove joint and the abuttingsides of the lower sheets 34 form a ship lap joint.

The end-to-end arrangement of the structural flooring panels 24 istypically chosen so that corresponding longitudinally extending,internal channels 38 of the structural flooring panels are axiallyaligned thereby to provide continuous internal channels 38 across thefloor structure. However, it will be appreciated that the structuralflooring panels 24 may be alternatively arranged in a non-aligned,axially offset or “staggered” pattern, provided internal channels 38 ofthe abutting structural flooring panels 24 are in fluid communication.

The longitudinally extending, internal channels 38 within the structuralflooring panels 24 provide passageways for services. In the buildingstructure 10 shown in FIGS. 1 a and 1 b, the longitudinally extending,internal channels 38 are used as ventilation ducts. To that end, turningback to FIG. 1 a, it can be seen that a heated forced air source 60,such as a furnace, rests on the foundation slab 12. A feed conduit 62extends from the heated forced air source 60 and delivers heated forcedair to the longitudinally extending, internal channels 38 of thestructural flooring panels 24. A cold air return conduit 64 returnsforced air exiting the opposite ends of the longitudinally extending,internal channels 38 back to the heated forced air source 60. The flowof heated air through the internal channels 38 results in heated floorstructures. Once heated, the structural flooring panels 24 also radiateheat into the interior of the building structure 10.

FIG. 1 b better illustrates the fluid connections between the floorstructures 18 and 20 and heated forced air source 60. Heated airgenerated by the heated forced air source 60 is transported through thefeed conduit 62 into a manifold duct 70, which runs the length of thefoundation wall 14 and along the underside of the floor structure 18.Manifold duct 70 is in fluid communication with a plurality of holes(not shown) formed in the lower sheets 34 of the structural flooringpanels 24 that are aligned with the internal channels 38. Manifold duct70 is also in fluid communication with one or more minor ducts 72. Eachminor duct 72 passes through the floor structure 18 and into arespective wall duct 74. The wall ducts 74 are formed between anexternal wall 22 of the building structure 10 and an interior skin 76,which in the embodiment shown is drywall. The width of each wall duct 74is defined by a pair of studs mounted vertically against the externalwall 22, and to which interior skin 76 is fastened. Each wall duct 74 isin fluid communication with structural flooring panels 24 forming theupper floor structure 20 of the building structure 10, through holesformed in the underside of each lower sheet that are aligned with theinternal channels 38. Reciprocal arrangements (not shown) exist forreturning cold air flow, which is directed back to the heated forced airsource 60 through the cold air return conduit 64.

Structural flooring panels 24 may be fabricated in standard sizes. Forexample, in the embodiment shown, each structural flooring panel 24 hasdimensions 4′×8′×10″ (width by length by thickness), however, structuralflooring panels 24 may also be fabricated in other sizes such as 4′×16′,or 4′×20′, for example. It will be appreciated that as the fabricatedlength of a structural flooring panel 24 is increased, its strength canalso be increased as desired by increasing the height of the ribs 36, byreducing the spacing of the ribs 36, and/or by increasing the width ofeach rib 36, and more specifically by increasing the thicknesses of theinsulation slab 42 and/or the rib sheets 40. Additionally, the strengthof the structural flooring panel 24 can be increased by strengtheningeither sheet 32 or 34, such as by increasing the thickness of the sheet32 and/or sheet 34 or by using sheets 32, 34 formed of a strongermaterial.

As floor areas can be of any size and shape, structural flooring panels24 can be readily cut to size on-site as needed to construct the floorstructure. A structural flooring panel 24 may be cut vertically throughits thickness without significant loss of structural integrity. Suchcutting may however result in loss of the joining formations provided onthe upper and lower sheets 32 and 34. In this event, furthermodifications can be made to a cut structural flooring panel 24 toenable joining with other structural flooring panels. FIG. 7 a shows a“site-crafted” joint between two adjacent side-by-side structuralflooring panels 24, in which a lumber spline 80 is inserted into one ofthe structural flooring panels 24 and generally parallel to the ribs 36.In this example, the tongue 44 and groove 46 of the upper sheets 32 ofthe structural flooring panels 24, and the lower and upper lap members48 and 50 of the lower sheets 34 of the structural flooring panels 24,have been removed as a result of cutting, leaving flat surfaces at thesides of the sheets 32 and 34. The lumber spline 80 is positioned midwaybetween the abutting sides of the sheets 32 and 34 so as to form a buttjoint between the structural flooring panels 24. In the embodimentshown, lumber spline 80 is oriented generally parallel to the ribs 36but non-parallel orientations may be used. The sheets 32 and 34 arefastened to the lumber spline 80 using screws, nails, adhesive or othersuitable fasteners.

FIG. 7 b shows an alternative site-crafted joint between twoside-by-side cut structural flooring panels 24, in which a lumber spline80 is similarly inserted into one of the structural flooring panelsparallel to the ribs 36. In this embodiment, rather than leaving theabutting sides of the structural flooring panel sheets flat, theabutting sides of the upper and lower sheets are appropriately notchedto form lower and upper lap members 48 and 50. The lumber spline 80 ispositioned midway between the abutting sides of the sheets and thesheets are suitably fastened to the lumber spline as described above.

Structural flooring panel 24 can also be modified on-site to provideadditional support for point or local loads imposed upon the structuralflooring panel 24, as needed. FIG. 8 shows a structural flooring panel24 in which two lumber sections 90 are inserted into an internal channel38 to provide local reinforcement between a pair of the ribs 36. In theembodiment shown, each lumber section 62 is a section of a lumber board,and has a length selected to provide an adequately-sized area ofreinforcement within the structural flooring panel 24, as desired.

FIGS. 9 a to 9 c show another embodiment of a structural flooring panel,generally indicated by reference numeral 124. Structural flooring panel124 in this embodiment similarly comprises an upper sheet 132, a lowersheet 134 and a plurality of laterally spaced, generally parallel ribs136 bonded to the sheets. Each rib 136 comprises a pair of rib sheets140, each of which is adhesively bonded to an opposite side of a foaminsulation slab 142. Cross-ducts 168 are formed in the ribs 136 toenable fluid communication between adjacent internal channels 138 withinthe structural flooring panel 124. In the embodiment shown, thecross-ducts 168 are circular bores provided through each rib 136 atspaced locations. The bores are arranged within structural flooringpanel 124 in a staggered pattern. As will be appreciated, thecross-ducts 168 can improve the temperature uniformity within thestructural flooring panel 124 when non-room temperature air is forcedthrough the internal channels 138.

FIGS. 10 a to 10 b show yet another embodiment of a structural flooringpanel, generally indicated by reference numeral 224. Structural flooringpanel 224 in this embodiment similarly comprises an upper sheet 232, alower sheet 234 and a plurality of laterally spaced, generally parallelribs 236 bonded to the sheets. Each rib 236 comprises a pair of ribsheets 240, each of which is adhesively bonded to an opposite side of afoam insulation slab 242. Vents 270 for allowing forced air provided tothe internal channels of the structural flooring panel to escape intothe interior of the building structure are formed in the structuralflooring panel 224. In the embodiment shown, one vent 270 is formed inthe upper sheet 232 in line with one of the internal channels 238 andone vent is formed in the lower sheet 234 in line with another of theinternal channels 238.

FIGS. 11 a to 11 c show yet another embodiment of a structural flooringpanel, generally indicated by reference numeral 324. Structural flooringpanel 324 in this embodiment similarly comprises an upper sheet 332, alower sheet 334 and a plurality of laterally spaced, generally parallelribs 336 bonded to the sheets. Each rib 236 comprises a pair of ribsheets 340, each of which is adhesively bonded to an opposite side of afoam insulation slab 340. A baffle 374 is positioned within one internalchannel 338, which partially obstructs that internal channel and therebyreduces the quantity of air flow along that internal channel. A plug 376is positioned within another internal channel 338 to completely obstructthat channel and thereby block all air flow along that internal channel.In the embodiment shown, baffle 374 and plug 376 are pieces of lumberboards.

FIGS. 12 a to 12 c show still yet another embodiment of a structuralflooring panel, generally indicated by reference numeral 424. Structuralflooring panel 424 in this embodiment similarly comprises an upper sheet432, a lower sheet 434 and a plurality of laterally spaced, generallyparallel ribs 436 bonded to the sheets. Each rib 436 comprises a singlerib sheet 440 adhesively bonded to one side of a foam insulation slab442. The use of only a single rib sheet, instead of two rib sheets,allows structural flooring panel 424 to be fabricated using a smallerquantity of material, resulting in a lower cost of fabrication.

Although the internal channels of the structural flooring panelsdescribed above are used to channel heated forced air through thestructural flooring panels, the internal channels of the structuralflooring panels may be used to channel cooled air or ambient air throughthe structural flooring panels. In this case, a cooled forced air unitsuch as an air conditioner or an ambient forced air unit such as ablower may be used to provide the forced cooled air or forced ambientair to the structural flooring panels. Of course, one flooring structuremay be provided with one type of forced air while another flooringstructure may be provided with another type of forced air.Alternatively, some of the internal channels of a structural flooringpanel may be provided with one type of forced air while other internalchannels of the structural flooring panel may be provided with anothertype of forced air.

Rather than acting as ventilation ducts or in addition to acting asventilation ducts, the internal channels of the structural flooringpanels may also be used to accommodate conduits through which utilitiessuch as plumbing and/or electrical wiring may be run. For example, theinternal channels may accommodate plumbing for a sprinkler system and/orconduit for electric wiring. Alternatively or in conjunction with thesprinkler system piping and/or conduit, the internal channels mayaccommodate piping for a radiant hot water system and/or other desiredservices.

If desired, the upper sheet, lower sheet, and/or rib sheets may be madefrom a fire-proof material (e.g. “Blaze Guard”) or treated with a fireproof material so as to increase the resistance of the structuralflooring panel to fire.

In the embodiments described above, the structural flooring panels areshown as comprising either cross-ducts, vents, or baffles and plugs, ornone of these features. Those of skill in the art will appreciate thatthe structural flooring panels may comprise a combination of thesefeatures.

Although the structural flooring panels are described as comprising ribshaving a “sandwich” structure, those of skill in the art will appreciatethat the ribs may take other forms. For example, the ribs may compriseboards or joists formed of suitable material. If desired, the spacingbetween the ribs and/or the longitudinal orientations of the ribs mayvary resulting in internal channels with different dimensions.

In the embodiments described above, the structural flooring panelscomprise first and second sheets formed of the same material. Those ofskill in the art however will appreciate that the first and secondsheets may be formed of different materials.

Although specific joints between adjacent structural flooring panels areshown and described, those of skill in the art will appreciate thatalternative joints between adjacent structural flooring panels may beemployed.

While the structural flooring panels are described as being fabricatedin sizes of 4′×8′×10″, 4′×16′ (×10″), or 4′×20′ (×10″), those of skillin the art will appreciate that the structural flooring panels mayfabricated in virtually any shape or size.

Although embodiments have been described above with reference to theaccompanying drawings, those of skill in the art will appreciate thatvariations and modifications may be made without departing from thespirit and scope thereof as defined by the appended claims.

1. A structural flooring panel comprising: an upper sheet; a lowersheet; and a plurality of longitudinally extending ribs between thesheets, the ribs being laterally spaced to define at least onelongitudinally extending, internal channel within the panel.
 2. Astructural flooring panel according to claim 1, wherein said ribs definea plurality of longitudinally extending, internal channels within thepanel.
 3. A structural flooring panel according to claim 2, wherein saidinternal channels are generally parallel.
 4. A structural flooring panelaccording to claim 3, wherein said internal channels extend generallythe length of said panel.
 5. A structural flooring panel according toclaim 4, further comprising at least one passage through at least one ofsaid ribs to bring adjacent internal channels into fluid communication.6. A structural flooring panel according to claim 5, comprising at leastone passage through a plurality of ribs.
 7. A structural flooring panelaccording to claim 6, wherein the passages provided through the ribs arestaggered.
 8. A structural flooring panel according to claim 4, furthercomprising at least one passage through at least one of said upper andlower sheets, said at least one passage being in fluid communicationwith an internal channel.
 9. A structural flooring panel according toclaim 8, comprising passages through at least one of said upper andlower sheets, each passage being in fluid communication with arespective one of said internal channels.
 10. A structural flooringpanel according to claim 3, wherein each of said upper and lower sheetsis formed of one of oriented strand board, plywood, fiberboard,particle-board, concrete sheet and magnesium-based sheet.
 11. Astructural flooring panel according to claim 3, wherein at least one ofsaid ribs comprises: a pair of rib sheets; and insulation between therib sheets, each of the rib sheets being bonded to an opposite side ofthe insulation.
 12. A structural flooring panel according to claim 11,wherein the rib sheets of the at least one rib are oriented so that theplanes of their major surfaces are generally perpendicular to the planesof the major surfaces of the upper and lower sheets.
 13. A structuralflooring panel according to claim 3, wherein each of said ribscomprises: a pair of rib sheets; and insulation between the rib sheets,each of the rib sheets being bonded to an opposite side of theinsulation.
 14. A structural flooring panel according to claim 13,wherein the rib sheets of each rib are oriented so that the planes oftheir major surfaces are generally perpendicular to the planes of themajor surfaces of the upper and lower sheets.
 15. A structural flooringpanel according to claim 3, wherein at least one rib comprises a slab ofinsulation, and a rib sheet bonded to one side of the insulation.
 16. Astructural flooring panel according to claim 15, wherein the rib sheetof the at least one rib is oriented so that the plane of its majorsurface is generally perpendicular to the planes of the major surfacesof the upper and lower sheets.
 17. A structural flooring panel accordingto claim 3, wherein each rib comprises a slab of insulation, and a ribsheet bonded to one side of the insulation.
 18. A structural flooringpanel according to claim 17, wherein the rib sheet of each rib isoriented so that the plane of its major surface is generallyperpendicular to the planes of the major surfaces of the upper and lowersheets.
 19. A structural flooring panel according to claim 13, whereineach of said rib sheets is formed of one of oriented strand board,particle-board, plywood and fiberboard.
 20. A structural flooring panelaccording to claim 19 wherein said insulation is formed of one ofexpanded polystyrene, honeycomb cardboard, extruded polystyrene andpolyurethane.
 21. A structural flooring panel according to claim 17,wherein each of said rib sheets is formed of one of oriented strandboard, particle-board, plywood and fiberboard.
 22. A structural flooringpanel according to claim 21 wherein said insulation is formed of one ofexpanded polystyrene, honeycomb cardboard, extruded polystyrene andpolyurethane.
 23. A floor structure comprising a plurality of abuttingstructural flooring panels according to claim
 2. 24. A floor structureaccording to claim 23 wherein said abutting structural flooring panelsare arranged side-by-side and end-to-end.
 25. A floor structureaccording to claim 24, wherein the internal channels of end-to-endstructural flooring panels are axially aligned.
 26. A floor structureaccording to claim 24, wherein the internal channels of end-to-endstructural flooring panels are axially offset.
 27. A floor structureaccording to claim 24, wherein abutting structural flooring panels carrymating formations.